To be fair to SSV they probably did get that snow accumulation.
I was there on Thursday and it was a genuine 21cm. I was surpised they didn't update it to more at 8am or noon as they have in the past to pump the numbers.
It snowed all day Thursday to add to the 21 but was getting beaten down. They quoted a 24hr accumulation which was 6amThurs to 6am Friday. Looks like you just picked the wrong day.